INDEX photooxidative

The reason of increased photooxidative stability is not only stabilizing activity of bis-aroilenbenzimidazoles derivatives but also the effect of these compounds on supermolecular structure of polymer matrix. As it is seen from the Table 6 physico - mechanical indexes of polymer do not practically depend on the method of additives introduction. Data of Table 6. agree with data of Table 5. In all cases the greatest degree of conservation of polymer initial properties is registered at the concentration of XLY compound - 1 mass %. 

Minerals often contain admixtures (such as free metals) which catalyze thermo-and/or photooxidation of the filled plastic. This subject will be considered in more detail in Chapter 15. Here we give just two examples of fading of CaCOs-fllled HDPE and polypropylene, with 76 and 80% w/w of the filler, respectively. The matrix had the melt flow index equal to 1 g/10 min (HDPE) and 8 g/10 min (polypropylene). Ashing of the both filled plastics at 525°C gave ash content of... 

Antiphotooxidative effect of carotenoids on the induction lime of soybean oil as measured by the Rancimat method. The effect of 100 ppm or 200 ppm capsanthin, P-carotene, or lutein on the photooxidative stability of soybean oil containing 200 ppm chlorophyll was measured by the Rancimat method after 4 hours light exposure at 2S°C. Preliminary studies showed that the induction lime of purified soybean oil containing 100 or 200 ppm carotenoids without chlorophyll was slightly lower than that of the blank sample which contained no carotenoids (data not shown. Therefore, there is no anti-autoxidative effect of carotenoids on the soybean oil- Table I shows that as the concentration of the carotenoids increased from 100 to 200 ppm, the induction time as well as the anti-photooxidation index (API) increased. The induction time of soybean oil containing the carotenoids was longer than that of (he control sample which contained no carotenoid however, it was still shorter than that of the blank sample which contained no carotenoid and no chlorophyll. 

Carotenoid (ppm) Induction lime (1T) Oirs) Anti-photooxidation index (API) ... 

Because of their excellent photooxidative durability, acrylic monomers are most often used in coatings. Hardness and softness, refractive index, chemical and humidity resistance, degree of durability, and degree of crosslinking are easily designed with an acrylic copolymer. Inherently, however, acrylic copolymers are not very flexible. To solve this problem, low 7g oligomers with acrylic functional groups are introduced in the formulation. 

Figure 1.4 Decay of dithlocarbamate absorbances and corresponding increases in carbonyl index in LDPE during photooxidation. 1, 2, 3 = carbonyl index growth curves for FeDMC, ZnDEC and NiDEC, respectively i = disappearance of visible absorbance of FeDMC 2 decay of ZnDEC, 280 nm absorbance 3 = decay of NiDEC 315 nm absorbance. (Reproduced from S. Al-Malaika, A M. Marogi and G. Scott, J. App. Polym. Sci., 31, 685 (1986), with permission).

Photolysis Chemical decomposition by the action of radiant energy Photooxidation Oxidation induced by radiant energy Refracture Index Measure of the biodegradability of a compound Sorption Reversible binding of a pollutant to a solid matrix Substituted Compound Replacement of one or more hydrogen atoms with other atoms or groups... 

Figure 13 Effect of processing conditions on photooxidative stability of PE containing additives (1 x 10" mol 100g ) (1) control processed for 10 min in closed mixer (10, CM) (2) control processed for 10 min in open mixer (10, OM) (3) FeDMC (10, CM) (4) FeDMC (30, OM) (5) FeAcAc (10, CM) (6) FeAcAc (30, OM). Insert shows the effect of FeDMC and FeAcAc (2.5 x lO" mol 100 g" ) on the melt flow index (MFI) of PP processed in a closed mixer of a RAPRA torque...

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